The research program detailed in this proposal is devoted to an electrophysiological analysis of acute and chronic effects of ethyl alcohol upon the simplest forms of neural plasticity, habituation and sensitization. The project will utilize the biological "model-systems" approach to a simplified vertebrate central nervous system, the monosynaptic lateral column--motoneuron pathway in the isolated spinal cord of the frog. This work will extend and complement studies on the same preparation which have yielded a partial determination of the synaptic processes accompanying and underlying vertebrate habituation and, specifically, will allow a characterization of the facilitative or disruptive effects of ethyl alcohol upon these processes. Three separate but interrelated sets of experiments will be conducted. I. whole nerve recordings of ventral root responses in normal and in alcohol-containing media during presentation of iterated lateral column stimuli and the accompanying habituation of response amplitudes, II. extracellular analyses of field potentials (focal potentials) to measure both pre- and postsynaptic contributions to alcohol-induced changes in responses and response plasticities, and III. intracellular recording from motoneurons to localize further the actions of alcohol upon the habituation process. A quantal analysis of transmitter release will permit quantification of alcohol effects on pre- and postsynaptic processes.